I started playing and turned a few settings up as I normally do with my new computer. Surprisingly I noticed a small degree of slowdown while playing the game. I did an MSI Afterburner test while playing the game and noticed that the game was using one of my four cpu cores at 100% and appears to be using the gpu very little.

I am using verion 1.04 of the game and i5-4690k, NVIDIA GeForce GTX 550 Ti with cooler master, which is probably how I was able to keep the single cpu from overheating.

Supposedly the 100% cpu usage was fixed in version 1.02, but I'm having this problem with 1.04. ref

I'm still looking up info on this issue, but I would be happy to hear any solutions here too.

Ok, got it. You need to turn of the cpu usage for the first core. If you do that then the other cores will handle the game equally, although I feel the gpu should be handling a bit more of the game than it does.

In Windows 7 start the game then go to the task manager via ctrl+shift+esc and right click Dust and set affinity. From there unclick the cpu that is running at 100%. To get the game to automatically never use the first cpu and use everything else right click on the shortcut and in Target set it to

C:\Windows\System32\cmd.exe /C start "" /affinity 0E "C:\GOG Games\Dust - An Elysian Tail\DustAET.exe"

0E = use cpu #2, #3, and #4. Here is the chart below.

01 - 1st CPU
02 - 2nd CPU
03 - 1st and 2nd CPU
04 - 3rd CPU
05 - 1st and 3rd CPU
06 - 2nd and 3rd CPU
07 - 1st 2nd and 3rd CPU
08 - 4th CPU
09 - 1nd and 4th CPU
0A - 2rd and 4th CPU
0B - 1st 2nd and 4th CPU
0C - 3rd and 4th CPU
0D - 1st 3rd and 4th CPU
0E - 2nd 3rd and 4th CPU
0F - 1st 2nd 3rd and 4th CPU

The values are added for the cpus you want to use. Therefore, 03 = 1st and 2nd CPU.

https://www.youtube.com/watch?v=ht4bV8IuWcM
http://www.tomshardware.com/forum/229129-28-affinity-prior-launch#2718243

That doesn't seem to work either. The next cpu just starts going up to 100% usage next :/ I'm not sure what the solution is, but at least I learned a trick for permanently setting the affinity of a program.

kk, I have another trick. Kinda odd, but after playing around with the settings by far the biggest improvement was playing in windowed mode as opposed to full screen.

The game is very likely made to only use one core. There are drastic architectural differences for an application to use multiple cores; using a GPU requires a completely different command set. For a game such as Dust, this using only one CPU is not a problem and actually to be expected.

This also means that no matter what you do, you *cannot* make the game run as multi-process. If you disable CPU affinity, that only means that the same, single process gets swapped apparently randomly between cores. This will *not* give you a performance boost.
In fact, disabling CPU affinity might be detrimental to performance and increase excess heat. Swapping between processors is costly because memory needs to be moved and may trash cashes. Since your CPU supports Turbo Boost, when using only a single core that one will actually run more efficient than when many cores are used, even if they are handling the same tasks a single core would be capable of.

TLDR:
Don't think you can do better process scheduling than your OS. If you have performance problems, turn the settings back down, e.g. reduce resolution (as windowed mode does implicitly).
Otherwise, stop worrying and enjoy the game.